In many of seats of cars and trains, various kinds of sofas and office chairs, a surface of a cushion body (foam) which is molded into a predetermined shape using foam resin is covered with covering material made of fiber fabric, or natural or synthetic leather. Some of the cushion bodies used for such various kinds of seats have concavo-convex curved surfaces which can satisfy ergonomic requirements to maintain a seating posture which prevents fatigue even if a user seats on the cushion body for a long time.
When the surface of the cushion body is covered with the covering material, after the cushion body is molded into a predetermined shape, a surface of the obtained cushion body is often covered with covering material and the covering material is fixed. Especially in this case, as means for fixing the surface of the cushion body and a back surface of the covering material to each other, a molded surface fastener is generally utilized.
In the molded surface fastener, a plurality of engagement elements (male engagement elements) are placed on one surface (first surface) of a flat base material made of thermal plasticity resin, and the molded surface fastener is integrally molded such that the engagement elements are exposed on the cushion body surface when the cushion body is molded. A back surface of the covering material which covers the cushion body is provided with a plurality of engagement elements (female engagement elements) which can be engaged with the engagement elements of the molded surface fastener.
When the cushion body on which the molded surface fastener is integrally molded is covered with the covering material, the female engagement elements placed on the back surface of the covering material are pressed against the male engagement elements of the molded surface fastener which is exposed on the cushion body surface, thereby engaging the covering material with the molded surface fastener. As a result, the covering material is easily fixed to the surface of the cushion body along the concavo-convex shape of the surface, and the covering material is prevented from floating up from the cushion body.
Such molded surface fastener which is integrally molded on the cushion body for fixing the covering material is disclosed in, for example, JP 2003-533314 A (Patent Document 1) and JP 2010-162339 A (Patent Document 2).
For example, in a molded surface fastener (fastening tool) 70 described in Patent Document 1, a plurality of surface fastener members (fastening segments) 71 are connected to each other through a flexible hinge 72 as shown in FIG. 16.
In Patent Document 1, each of the surface fastener members 71 includes a base portion 73 provided at its front and back with a fastening surface and a non-fastening surface, a plurality of engagement elements 74 which stand on the fastening surface of the base portion 73, and a gasket 75 which is placed around an outer peripheral edge of the base portion 73 to surround the plurality of engagement elements 74. In this case, each of the engagement elements 74 is configured as a palm-shaped male engagement element having a bifurcated upper end. The gasket 75 is higher than the engagement elements 74 in height as measured from the base portion 73.
Further, in the molded surface fastener 70 of Patent Document 1, the plurality of surface fastener members 71 are connected to each other through the hinge 72. Accordingly, the molded surface fastener 70 can be bent in a front-surface/back-surface direction or a width direction, and can be twisted around a longitudinal axis.
When the molded surface fastener 70 of Patent Document 1 is integrally molded on a cushion body, a tip end of the gasket 75 of the surface fastener member 71 is brought into contact with a cavity surface of a mold, the molded surface fastener 70 is sucked and fixed to a predetermined position of the mold by utilizing a magnetic force and then, foam resin material is injected into a cavity space of the mold. Accordingly, a cushion body with which the molded surface fastener 70 is integrally molded can be obtained.
At that time, the plurality of engagement elements 74 in each of the surface fastener members 71 are surrounded by the gasket 75, and the tip end (upper end) of the gasket 75 is in contact with the cavity surface of the mold. Therefore, the plurality of engagement elements 74 are confined by the gasket 75 and the cavity surface of the mold. Hence, when the foam resin material is injected into the cavity space of the mold, it is possible to prevent the foam resin material from flowing over the gasket 75 of the surface fastener member 71 into an inside region where the engagement elements 74 are placed.
Therefore, even though the molded surface fastener 70 of Patent Document 1 is integrally molded with the cushion body, it is possible to prevent the engagement element 74 of each of the surface fastener member 71 from being buried in and hidden by the foam resin, and the plurality of engagement elements 74 are exposed on the fastening surface in the surface fastener member 71. Therefore, an engaging/connecting force of the engagement elements 74 with respect to the covering material is appropriately secured.
Further, the molded surface fastener 70 of Patent Document 1 can be bent and twisted as described above. Therefore, even if a surface of a cushion body to be molded has a concavo-convex curved surface, the molded surface fastener 70 can integrally be molded with the cushion body in a state where the molded surface fastener 70 curves in the width direction and the front-surface/back-surface direction such that the molded surface fastener 70 matches with a surface shape of the cushion body.
Therefore, when the molded cushion body is covered with the covering material, the covering material is engaged with and connected to the molded surface fastener 70 of the cushion body. According to this, the covering material can be fixed along the concavo-convex shape of the cushion body surface, and it is possible to prevent the covering material from floating up from the cushion body.
As shown in FIG. 17, a molded surface fastener 80 of Patent Document 2 includes a plurality of surface fastener members 81, and flexible connecting portions 82 for connecting the surface fastener members 81 to each other along a longitudinal direction. Each of the surface fastener members 81 includes a flat plate-shaped base material 83, and a plurality of engagement elements (male engagement elements) standing from one surface of the flat plate-shaped base material 83.
In this case, each of the engagement elements 84 includes a standing portion which stands from the flat plate-shaped base material 83, and a pair of engaging heads which is bifurcated from an upper end of the standing portion and which curves into hook shapes. The plurality of engagement elements 84 are arrayed at predetermined distances from one another in the longitudinal direction and the width direction of the surface fastener member 81. According to this, an engagement element region 85 which can be engaged with and connected to the covering material is configured.
A pair of left and right longitudinal protective wall sections 86 is placed along the longitudinal direction on each of both left and right side edges sandwiching the engagement element region 85 in each of the surface fastener members 81 in the width direction. Lateral protective wall sections 87 are formed between the left and right longitudinal protective wall sections 86 along a row of the engagement elements 84 which are arrayed in the width direction. First fixing portions 88 and second fixing portions 89 are provided on the lateral protective wall sections 87 of the surface fastener member 81 such that the first fixing portions 88 and the second fixing portions 89 project from the flat plate-shaped base material 83. The first fixing portions 88 bury and fix a monofilament configuring the connecting portions 82 along the entire region of the surface fastener member 81. The second fixing portions 89 fix linear magnetic materials 90 at positions of the lateral protective wall sections 87.
The longitudinal protective wall sections 86 of Patent Document 2 include three rows of longitudinal wall sections on each of the left and right sides. Each of the longitudinal wall sections includes a plurality of longitudinal wall bodies 86a which are arrayed at a predetermined pitch from one another in the longitudinal direction. In this case, the longitudinal wall bodies 86a are arranged in a zigzag manner between the adjacent longitudinal wall sections such that the longitudinal wall bodies 86a are staggered from one another. The lateral protective wall sections 87 include the engagement elements 84 which are arrayed in the width direction, and a plurality of divided lateral wall bodies 87a which are arranged such that they are divided from one another in the width direction.
When the molded surface fastener 80 of Patent Document 2 having the above-described configuration is to be produced, a continuous long primary surface fastener member before it is divided into the plurality of surface fastener members 81 is first produced. The primary surface fastener member is produced using a producing device that includes a die wheel which rotates, an extrusion nozzle which supplies molten resin to a peripheral surface of the die wheel, and a supply portion which supplies a monofilament and linear magnetic material from an upstream side of a position where the molten resin is supplied to the die wheel. In this case, cavities for forming the engagement elements 84, and cavities for forming the longitudinal wall bodies 86a and lateral wall bodies are formed in the peripheral surface of the die wheel.
After the long primary surface fastener member is produced using such a producing device, a portion of the obtained primary surface fastener member is entirely cut in the width direction at an arbitrary position in the longitudinal direction such that a monofilament configuring a connected portion is left. Accordingly, the molded surface fastener 80 of Patent Document 2 as shown in FIG. 17 is produced.
According to the molded surface fastener 80 of Patent Document 2 produced in this manner, when the cushion body is foamed and molded using a mold, a linear magnetic material 90 of the molded surface fastener 80 is attracted using a magnetic force of a magnet which is previously placed in the mold, and thereby the engagement elements 84 are attracted by and fixed to the cavity surface of the mold such that the engagement elements 84 face the cavity surface. At that time, by bending the connected portion, the molded surface fastener 80 curves in the width direction and the front-surface/back-surface direction. In this state, the molded surface fastener 80 is attracted by and fixed to the cavity surface of the mold, and in this curved posture, the molded surface fastener 80 can integrally be molded with the cushion body.
The engagement element region 85 of the molded surface fastener 80 is surrounded by the longitudinal protective wall sections 86 and the lateral protective wall sections 87. When the cushion body is foamed and molded, upper end surfaces of the longitudinal protective wall sections 86 and the lateral protective wall sections 87 come into close contact with the cavity surface of the mold. Accordingly, foam resin material injected into the cavity space of the mold is prevented from flowing over the longitudinal protective wall sections 86 and the lateral protective wall sections 87 of the surface fastener member 81 and from flowing into the engagement element region 85.
Especially, in Patent Document 2, the longitudinal protective wall sections 86 include the plurality of longitudinal wall bodies 86a which are arranged in the zigzag manner at the predetermined pitch from one another. The longitudinal wall bodies 86a are separated from one another. In this case, even if the foam resin material tries to enter the engagement element region 85 through gaps formed between the longitudinal wall bodies 86a of the longitudinal protective wall sections 86, it is possible to prevent the foam resin material from entering the engagement element region 85 since the foam resin material is foamed and solidified before it reaches the engagement element region 85. Therefore, according to the molded surface fastener 80 of Patent Document 2, even if the cushion body is foamed and molded, the engagement element region 85 of the molded surface fastener 80 can be appropriately exposed on the surface of the cushion body to stably secure the engaging/connecting force of the engagement element region 85.